Hitherto, there has been known a truss support device for a passenger conveyor, in which end portions of a truss are mounted on a bearing plate arranged on a building portion, and a pair of stopper members are arranged at positions of sandwiching the end portions of the truss in a width direction of the truss, to thereby regulate a displacement of the end portions of the truss in the width direction while allowing a displacement of the end portions of the truss in a longitudinal direction. The pair of stopper members are fixed to the bearing plate by being arranged along side surfaces of the end portions of the truss in the width direction under a state of being brought into contact with the side surfaces of the end portions of the truss in the width direction (see Patent Literature 1).